Head-Mounted Device With Optical Module Illumination Systems

To accommodate variations in the interpupillary distances associated with different users, a head-mounted device may have left-eye and right-eye optical modules that move with respect to each other. Each optical module may have a display that creates an image and a corresponding lens that provides the image to an associated eye box for viewing by a user. The optical modules each include a lens barrel to which the display and lens of that optical module are mounted and a head-mounted optical module illumination system. The illumination system may have light-emitting devices such as light-emitting diodes that extend along some or all of a peripheral edge of the display. The light-emitting diodes may be mounted on a flexible printed circuit with a tail that extends a lens barrel opening. A stiffener for the flexible printed circuit may have openings that receive the light-emitting diodes.